As well as being the founder of defense company Raytheon and heading the Office of Scientific Research and Development during World War II, Vannevar Bush is remembered for his Differential Analyser, an early analog computers, and for introducing a concept that we now consider the hyperlink. He died on June 28, 1974 at the age of 84.

Vannevar Bush

March 11, 1890 - June 28, 1974

The story of Vannevar Bush is one of the strangest of the pioneers of computing. Who else can you think of who positively disclaimed any credit for the invention of the digital computer:

"Who invented the computer? I can write at once that I did not: in fact I had little to do with that whole development".

In fact he had rather more to do with computing than he was letting on. He built several analog machines, which he owned up to, and started building one of the earliest digital computer which he seemed to have forgotten all about! And he introduced a concept that can be considered the forerunner of the hyperlink that is now so prevalent in the interconnected Web.

Vannevar Bush considered himself an inventor. He had a finely honed instinct for mechanical devices. While an undergraduate he designed an amazing device that measured ground levels. You rolled it over the terrain and it drew a graph of the change in height. The device was purely mechanical but it included an integrator - the basic component needed to build an analog computer. It worked by summing up the changes in height to give the current height.

The machine was so impressive that he was awarded both a patent in 1912 and a degree on the basis of it. He then moved on to a PhD in electrical engineering at MIT and Harvard.

The profile tracer

Although he was keen on mechanical engineering he specialised in the relatively new subject of electrical engineering.

He wrote a textbook on the mathematical analysis of circuits and taught a course so popular that he had to recruit more lecturers. Eventually he realised the other lecturers knew more about the subject than he did and he handed the course over to them and the responsibility for producing a newer volume.

Bush always felt that handing on the work to younger people was a good thing to do. He was a generous man who never failed to give credit and/or responsibility to others - and this goes some way to explaining why he was so quick at disclaiming all responsibility for inventing the digital computer!

Another important feature of Bush's character is that he really did enjoy tinkering with machinery and he thought of himself as an inventor - more to the point an inventor without the artificial barriers of subject classifications.

Later in his career he took charge of a pharmaceutical research lab even though he knew little about chemistry. He had a liveliness of mind and a confidence that intelligence and problem solving ability could do anything that is often lacking in today’s over-compartmentalised world.

He drove a steam car, a Stanley Steamer, for many years and came to an easy understanding of its workings. He mastered the art of coaxing it up icy hills to see his future wife and of avoiding major fires.

A 1908 Stanley Steamer

One day when it flooded and caught fire he sat by the side of the road waiting for it to go out but a traffic cop turned up and complained that if he wanted to burn his car there was a municipal dump just up the road. He explained that it was only a matter of time but the traffic cop wasn't convinced. When the fire eventually went out he drove away on the full head of steam that had built up leaving behind a bewildered traffic cop.

He worked for General Electric for a while but eventually found his way back to MIT as a professor of electrical engineering. Eventually he would rise to become the head of the faculty.

His first steps into the world of computing were taken because of the need to solve equations. This is the recurring need that drove computer development in the early years.

Towards the Differential Analyzer

Bush wanted to solve equations that related to power line transmission. This was a big problem back in the early days of electrification where exactly how electricity could be transmitted over long cables was a practical concern.

These were differential equations that took months to solve. Bush decided that a quicker route to the solution was an analog computer. The MIT electrical engineering department spent the best part of 20 years on the project!

Bush first suggested the idea in 1925 and his students worked on the problem. They jointly invented an electromechanical multiplier and integrator.

By 1928 they had a very basic machine working and this proved that is was possible. Bush had lots of help with ideas from his students and it does seem that it was a joint invention but there is no doubt that it would not have worked without Bush guiding the project. At each step he attempted to replace mechanical components with electromechanical ones.

First “thinking machine”

At the end of 1928 he had funds to build an even larger machine. This was a big machine - almost as big as a digital machine. It had servo mechanisms where possible to make the mechanical components more accurate.

This is the machine that Douglas Hartree saw and copied back in Manchester - only he used Meccano on a budget of £20.

The complete Differential Analyzer

Today we think of the MIT Differential Analyser as a number cruncher of a very specific and technical nature but at the time it was hailed as the first “thinking machine”. The New York Times ran an article with the headline “Thinking Machine Does Higher Mathematics”.

In 1936 Bush delivered a paper to the American Mathematical Society entitled 'Instrumental Analysis'. It discussed the work of Charles Babbage and his attempts to build an analytical engine. Bush thought that by linking together some IBM punch card machines under the control of a central programmer he could build a close approximation to Babbage's machine. It was clear that Bush had understood Babbage’s work and the idea of programmability.